how do I get rid of the "Downloads complete" notification box?

How do I get rid of the small "Downloads complete" notification box that comes up in the lower right corner of the monitor when all files are finished downloading? I've looked everywhere for a switch to shut it off but cannot find one. Any ideas?

How do I get rid of the small "Downloads complete" notification box that comes up in the lower right corner of the monitor when all files are finished downloading? I've looked everywhere for a switch to shut it off but cannot find one. Any ideas?